1. Field of the Invention
This invention relates generally to lightweight spare wheels and, more particularly, to lightweight spare wheels that include a lightweight rim and a lightweight tire, and a system and method for monitoring the use of spare wheels.
2. Discussion of the Related Art
Maximizing fuel efficiency in vehicles is a major concern of automotive engineers. With respect to spare tires or wheels, the use of a temporary spare tire provides the benefit of taking up less storage space and is lighter than a full-sized tire, thus providing better fuel efficiency and increased spaciousness, as well as ease of handling during a tire change.
A typical spare tire rim is made from a suitably strong and durable metal alloy material, such as steel or aluminum. Steel rims are typically around 8 kg, and aluminum rims are typically about 5.5. kg. In a full size tire with thick tread sections and heavy steel and/or polyester belts, the average weight of the resulting rim and tire assembly, i.e., the wheel, is approximately 12 kg. A compact spare tire with thick tread sections and heavy steel and/or polyester belts has an average weight of approximately 6 kg. While this is lighter than the full size wheel, there is still a need in the art to reduce the weight of spare tires. The lowered weight or mass of the spare tire translates to a lower mass of the overall vehicle, which is expected to lead to an improvement in fuel economy.
Another consideration for engineers when dealing with spare tires is safety. While vehicle tire systems that monitor characteristics such as tire pressure are known, for example, as disclosed in U.S. Patent Application Publication No. 2011/0000596 to Sachdev et al., entitled “Low Noise Run-Flat Tires”, filed Jul. 2, 2009, assigned to the assignee of this application and incorporated by reference, these systems do not detect the use of a spare tire. Currently, once a spare tire is installed there is no mechanism to indicate that the spare tire has been installed or to track how long it has been on the vehicle. Thus, there is also a need in the art for a system and method that detects the use of a spare tire and that warns the driver when the spare tire is reaching the end of its life.